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Auto guiding with an EM 200: Celestron NexGuide ?

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#1 kurtfriedrich

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Posted 13 March 2018 - 05:05 PM

I have an EM 200, currently autogude using a laptop.

 

Would like to use this Celestron  NexGuide  (  https://s3.amazonaws...glish_Final.pdf

 

The NExGuide says "Telescope Mount:  The mount must

have a dual-axis motor drive with “ST-4” compatible autoguiding port."

 

Does the EM 200 have such a port?  I know it does not have the same telephone type jack input, but if I make my own cable adapter, will it work?

 

The spec for the EM  says "Autoguiding SBIG ST-4/7 compatible"  and also

The control panel features an autoguide port (compatible with SBIG CCD cameras) as well as a RS-232 serial port

 

Goto operations will have to be done through a RS-232 cable (supplied) connected to a PC equipped with Pegasus 21 software (supplied) or any other software compatible with the Temma protocol.

 

Thanks.



#2 orlyandico

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Posted 13 March 2018 - 08:20 PM

The EM200 does have an ST4 port. It has that weird DIN connector but is electrically an ST4 port.

#3 Dwight J

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Posted 14 March 2018 - 04:18 AM

The connector on the mount should read "Autoguide".  You can get the appropriate cable from Texas Nautical Repair.  As with many things Tak, it ain't cheap.  Once you get it up and guiding I would like to hear about your results with the stand-alone gider and the EM200 as I am considering that approach.



#4 jwheel

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Posted 14 March 2018 - 10:09 AM

You can also get an adapter from shoestring astronomy. I use this one on my Tak mount and it works great!

 

http://www.store.sho...m/gpcnv_tak.htm



#5 kurtfriedrich

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Posted 14 March 2018 - 01:23 PM

Thanks much for all the help.  Ordered the NexGuide on sale and the cable from Shoestring.

 

Worried that the NexGuide will not work with fainter guide stars in areas where I may want to shoot, but we shall see.

I figure I'll pick my targets based on availability of good guide stars and see if I can get some successes.

 

Assuming the clouds ever clear in Seattle!



#6 orlyandico

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Posted 14 March 2018 - 05:07 PM

The Nexguide is notorious for its poor sensitivity. Hope you have at least an 80mm guide scope.

#7 kurtfriedrich

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Posted 14 March 2018 - 05:42 PM

I use a low budget Orion 90mm  500mm focal length (f/5.6), maybe that will be good enough for Orion’s Alnitak as a guide star while I chase the flame/horse head!



#8 orlyandico

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Posted 14 March 2018 - 11:05 PM

90mm should be plenty grin.gif

 

i use a 50mm finder guider, and the NexGuide is not up to that small of a scope.



#9 kurtfriedrich

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Posted 17 July 2018 - 02:14 PM

Well, thanks to the help I got here, I got this setup working.  I got the shoestring astronomy cable. So far I just tried it out 2 nights. First night I used a very bright guide star, but 2nd night I picked a fairly random spot in the sky and used a star of some magnitude which I am pretty sure I could generally find near a photo target.  I did 3 8 minute shots, all of which came out great.  This is all on an EM-200 using an Orion 90mm  500mm focal length guide scope, with an AP 140 and a Canon  Rebel SL1.  I'm pretty happy so far.  Hopefully tonite I'll use it for a real photo session.  Here is one of the pics, reduced to 1/2 the pixels. Nexguide%208minTrack0DecBacklashMedium.J


Edited by kurtfriedrich, 17 July 2018 - 02:16 PM.


#10 kurtfriedrich

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Posted 17 July 2018 - 02:24 PM

I got it on sale for $139 including shipping, I see one used out of NY for $309, and one from Japan at $500!  I think it was a good buy at $139.



#11 kurtfriedrich

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Posted 21 July 2018 - 04:22 PM

I set up on July 18 and got 12 pics before the clouds came in, then again on July 20, with a bit of moon interference, and got 31 more.  All 4 min shots.  Guider worked great, and with my 90mm guide scope, finding a guide star around the Cocoon was not hard at all.

 

CocoonNebJuly18and21_18_42x4min1600med.j


Edited by kurtfriedrich, 21 July 2018 - 09:23 PM.


#12 orlyandico

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Posted 23 July 2018 - 06:23 PM

glad it works for you!

 

$139 is a good price. $300 or $500 is not. There are much better choices at the latter prices (e.g. Lacerta MGEN II).




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